Improved volttte spring



'r fcited 5mm Mesem-MW JOSEPH TRENT, MILLERTO'N, YORK. Letters Patent .Nlo. 86,713, dated Febfrua/ry 9, 1869.

RVEPRQVED VOLUTE SPRING.

To all lwhom it ma/y concern Be it known that I, JOSEPH TRENT, of Miller-ton, in the county of Dutchess, and State of New York, have invented a new and improved Ooiled Yor Volute Spring, which Iterxn a semi-elliptic volute spring; and I do hereby declare that the following is a tull, clear, and

exact description of the same, reference being had to the accompanying drawing, which forms part of this specification This invention relates to that class of springs termed volute springs, of which I will mention four kinds, the single -or old-fashioned volute spring, the double or Rollins volutespring, the'double or Freeland 8a Ward vohrte spring, and the quadruple or Trent volute spring. All of these are made by coiling or rollingup, usually around a mandrel, a plate, or strip of metal, of a certain denite shape, i

It has been demonstrated that strips of different forms and shapes, when rolled or coiled up, constitute springs of different qualities and powers; hence the practical utility of the spring is not really due to the manner of coiling the sheet or strip, but to the peculiar shape of the strip or plate of metal used to make the spring; therefore the shape given to the strip con-T stitutes an invention, inasmuch, as before stated, strips of diii'erent shapes produce springs possessing widelydifferent powers and modes of operation.

My present invention consists `in a new article' of manufacture, to wit, a spring constructed of 'a strip of metal, which, before it is coiled or rolled up, is, as to a portion of its length, semi-elliptical, or nearly so, in shapev or form, and which spring, when s o made, may properly be termed a semi-elliptical volute spring.

In the accompanying drawing- Figure l is a side elevation of the strip of metal, which, when coiled orrolled up, constitutes the spring.

Figure 2 is a side elevation of the spring which forms the subject of this application for patent.

Figure 3 is a vertical central section of the said spring. v

A designates the plate or strip of metal used to construct the spring.

Said strip is semi-elliptical in shape, as to its main.

portion, a, and has two horizontal legs or arms, b b', one at each terminus of the semi-elliptical portion, a. One of these legs, b, is represented as of greater length than the other, b', and when the strip is coiled,it produces an even base for the spring, the shorter leg, b',

constituting the core of the spring; and I will remark that this shorter leg, b', is not absolutely essential, though I find it preferable to terminate the strip in such way. i

Itis vevident that a great number of these strips can be stamped out of a series of metallic-plates byan ordinary metal-cutting press, and it is also' obvious that in cutting a number of the strips out of a sheet, there will be but little waste of metal, inasmuch as the strip is of such shape that the knife, by one descent, cuts not only the lower edge of one strip, but the upper edge of the next succeeding strip; hence seven knives, arranged parallel with each other, will cut live strips, the only waste metal being at the top and bottom corners of the sheet. This is really an important advan` tage gained in the manufacture of such springs.

The strip, when cut, may be rolled up or coiled in any suitable manner. The usual practice, as hereinbefore stated, is to coil them around a mandrel, in a manner well known to those skilled in the art.

The operation of this spring, when subjected to weight, is as follows:

The upper coils are rst depressed, an easy springing motion being produced. The flexibility ofthespring having been exhausted as to these coils, a united ac.- tion of these coils sinking downward on the core, (the latter pressing on the plate or base on which the spring rests,) takes place. The compression of these parts increases in proportion to the weight on the spring. This will be fully understood by referring to iig. 3, where the position of the coils before any compression takes place is illustrated.

A spring of the character herein described will securely maintain its vertical position, there being no spring, which I term a semi-elliptic volute spring, constructe'd in the manner herein set forth.

JOSEPH TRENI.

Witnesses:

J onu Mc QUEEN, M. M. LIvINesToN. 

